Matthew Fisher-Turner murder: Father's alleged jail confession

A court has heard a Perth father accused of killing his son before watching the AFL grand final allegedly confessed to planning the murder.

Ernest Albert Fisher is accused of murdering Matthew Kyle Fisher-Turner in 2016 and then ordering his other children, Joshua and Hannah to bury his body in the backyard.

Ernest Fisher is accused of killing his son. Picture: 9NEWS (9NEWS)

The mother of one of Mr Fisher-Turner's girlfriends gave evidence at court today, revealing she had visited the family home while he was reported missing when Mr Fisher told her his son went over east "with a hot chick".

She said Mr Fisher also told her his son had punched holes in the bedroom door and showed a bruise on his ribs, claiming Mr Fisher-Turner did it.

But, she says when she saw him later in Hakea prison, Mr Fisher confessed he didn't want his son around and that he had bought sharp knives and hid them in a shed while waiting for "the right time to dispose of Matt".

Matthew Fisher-Turner's body was found at his family home. Picture: 9NEWS (9NEWS)

She also said Mr Fisher told her Mr Fisher-Turner started yelling at him about wanting to borrow the car and "that's when he knew he was going to kill him."

Prosecutor Laura Christian told the Supreme Court of Western Australia yesterday that Mr Fisher, then 65, stabbed his son two or three times with two sharp knives, puncturing his aorta and a lung.

He told detectives he'd said "I'm not having it" and football was his priority that day.

After the killing, he started digging a grave in the backyard then left the house to watch the match, leaving it up to his two other children - Joshua to bury his brother and clean up blood, while Hannah helped carry the body outside on a ladder, Ms Christian said.

Mr Fisher-Turner was buried in the backyard of the Parmelia property. Picture: 9NEWS (9NEWS)

Mr Fisher will argue he killed his son in self-defence after years of abuse.